8. Some Unintended Consequences of Feeding Hedgehogs

Here’s one – but you have to admire the style.

Why it didn’t use the steps just to the right is beyond me. And of course where you have one, you’ll have another.

I am no expert but these are most likely Rattus norvegicus – the common-or-garden brown rat – in this case a garden rat. They have only recently [second half of November] started to appear on camera. They are much less frequently recorded than hedgehogs or cats but that could be because their smaller size is less readily detected by the camera’s useless motion sensors. Where the hell the cats are when they are wanted is another unanswered question, and the same goes for the tawny owl audible in the background in some of the videos. The rats seem to be out and about most when the weather is wet – as in the above videos.

Rats are a fact of life. They have certainly been in my garden as long as I have and have not just arrived with the resurgent hedgehogs, but they normally avoid propinquity to humans, in spite of their being commensal with us, unless they have good reason not to – in this case the presence of a rat’s equivalent of a free lunch served up every night to urchins.

Also recorded are the rats’ more endearing cousins, the wood or field mouse Apodemus sylvaticus. There are three in the next video – none of them blind and not a clock in sight.

Equally as talented at climbing as rats, the mice make nothing of the overhang at the top of the climb. Watch out for similar human skills in the 2020 Olympics, when climbing walls will feature for the first time.

The mouse made a dozen or so such trips; into the feeder then out with a cat biscuit – about the size of a split pea – before legging it up the wall presumably to where it lived. As for controlling these uninvited visitors I shall let nature take its course with the mice but the rats are something else and need discouraging. Poison is of course out of the question and anything other than live trapping could be hazardous to the very critters I wish to encourage. So I plan to install this.


Hedgehogs are by nature inquisitive. Give them a hole and they are sure to poke their head in, so the entrance to the rat trap will have to be reduced in size to admit rats but not hedgehogs.

rat trap

The finished structure has a roof on it. Rats are waur, canny craiters so the trap has been put in position unbaited and unset for a few days to ‘weather’. Any rats caught will be marked before being taken about two miles away and released. It will be interesting to see if any reappear.

Of more concern is possible disruption of the hedgehogs’ natural behaviour. Hibernation is not the same as sleep. It seems to be a more-or-less conscious decision along the lines of the Micawber Principle*; a cost benefit calculation based on energy expended for reward gained. As the temperature cools, with the onset of winter the abundance of available food declines to a point where its nutritional benefit is outweighed by the effort to find it. At this point a well-nourished hedgehog hits the sack. A ‘well-nourished’ hurcheon is apparently one weighing about 1ΒΌ lbs or more. A hedgehog weighing less than that is unlikely to survive hibernation as it will simply run out of fuel. If found, they need adopting, housing, keeping warm and feeding. See the internet e.g. Hedgehog Street

Hedgehogs of the species Erinaceus europaeus do not invariably hibernate. Those introduced to New Zealand from Britain for example rarely do so as food remains sufficiently plentiful during their winters. But I live in Somerset, G.B. By ensuring a regular supply of food, might I be interfering with hedgehogs’ natural hibernation behaviour? Were there to be snow lasting, say, a fortnight, by no means unheard of, albeit something of a rarity these days, the hedgehogs that currently visit my garden to feed may not have established a safe and secure place in which to hibernate, let alone made the necessary physiological adjustments. And as Peter’s grumpy grandfather (cf. ‘Peter and the Wolf’) might ask querulously, “what then?” This is a problem for which I do not at present have any answer.

* Because, were Mr Micawber a hedgehog he might have said; Nightly intake of food one hundred calories, nightly expenditure of effort ninety-nine point five calories, result happiness. Nightly intake of food ninety-nine point five calories, nightly expenditure of effort one hundred calories, result misery. Or death from starvation.